Hypo jet injector



y 1956 R. P. SCHERER 2,754,813

HYPO JET INJECTOR Filed June 24, 1950 5 Sheets-Sheet l y 1956 R. P. SCHERER 2,754,313

HYPO JET INJECTOR Filed June 24, 1950 5 Sheets-Sheet 2 [72 venfar EzQgerf $904976) 4 292702 2215395 y 1956 R. P. SCHERER 2,754,818

HYPQ JET INJECTOR Filed June 24, 1950 5 Sheets-Sheet 3 awk 2m J y 1956 R. P. SCHERER 2,754,818

HYPO JET INJECTOR Filed June 24, 1950 5 Sheets-Sheet 5 United States Patent HYPO JET INJECTOR This invention relates to an injector for hypodermically injecting fluid by the jet therapy method disclosed in my copending application, Serial No. 77,517, filed February 21, 1949, and now Patent No. 2,704,542, March 22, 1955. The disclosure in the present application is a practical embodiment of the elementary form of hypo jet injector disclosed in a second copending application, Serial No. 94,579, filed May 21, 1949, and now Patent 2,704,543, March 22, 1955. The injectors of the present application and of the copending application just mentioned use a hypo jet ampule of the type disclosed and claimed in a third copending application, Serial No. 93,282, filed May 14, 1949, and now Patent No. 2,688,968 of September 14, 1954.

One object of the present invention is to provide a hypo jet injector including a powerful spring-actuated propelling means for the liquid to be hypodermically injected and a practical and efficient mechanism for manually compressin relatively powerful springs of the mechanism without prohibitive escort.

Another object is to provide a mechanically practical means for suddenly releasing the stored-up energy in the springs to effect the propulsion of a plurality of plungers in a desired sequential manner for producing a desired and controllable pattern of multiple-stage jet injection. Such pattern includes, with the present disclosed injector, a low-pressure second stage following a first stage effected at a relatively high pressure and high velocity, that is high enough to produce a penetrating jet that opens a hole or channel by distending action through the epidermis to the desired depth in the underlying fat tissues, through them to the fascia overlying the muscles if desired, or if required through the fascia itself and into the muscle therebeneath for thereafter permitting in intra-muscular injection to be made, most injections however, being intra-fascial or merely hypodermic (in the fat tissues without going as deep as the fascia). With even less pressure in the first stage it is possible to go through only the epidermis and make intra-dermal injections.

The low pressure or second stage of the injection then consists of continuing the jet of medicament but with less pressure and velocity to produce what may be termed a follow-through jet so that the medicament is discharged into the opening or channel formed by the high pressure penetrating jet and is dispersed laterally by the follow-through jet from the bottom of the channel, generally parallel to the fibers of the tissues at the desired depth hypodermically.

Another object is to provide a hypo jet injector formed of two sections, one a relatively compact yet rugged power section and the other an adjustable metering section for the dose of medicament, the operation of the injector being such as to effect true jet therapy with a mechanism that is of practical size and weight for average use and yet is not prohibitively complicated to operate.

A further object is to provide a power spring arrangement comprising a plurality of coil springs arranged parallel to each other within an elongated body of the injector,

2,754,818 Patented July 17, 1956 and a screw threaded means for compressing the springs with comparatively little effort by rotation of a winding sleeve on the body, a novel type of latch mechanism being provided for holding the springs compressed and releasing them in an efficient manner without appreciable wear on the latch mechanism, complete details thereof being disclosed and claimed in my copending application, Serial No. 170,102, filed June 24, 1950, now Patent No. 2,671,347.

Still a further object is to provide a hypo jet injector constructed for producing a high penetrating pressure and a lower follow-through pressure in the jet issuing therefrom, and for effecting a quick cut-off of the pressure and the liquid flow at the end of the injecting operation.

An additional object is to provide a dosage adjusting sleeve on the body for reducing the dosage if desired to any value less than the full charge of the ampule. This dosage sleeve is micrometrically calibrated for securing accuracy of dosage.

Another additional object is to provide an adjustment by means of a calibrated rotatable winding sleeve to permit adjustment of the penetrating jet from the maximum of which the instrument is capable to the minimum or the follow-throng pressure, thus making the injector adjustable for intra-dermal, intra-fascial or merely hypodermic injections as well as intra-muscular injections.

Still another additional object is to provide an ampule holder which substantially encloses the entire ampule so that the ampule may be formed of relatively light sheet metal and yet cannot expand appreciably, when subjected to high hydraulic pressures within the ampule. Thereby it is practical to provide disposable ampules with the charges of medicament sealed therein.

A further additional object is to provide an ampule holder covered with rubber or similar resilient material for non-slip contact with the patient. The resilient material also seals the ampule and prevents the liquid purposely predischarged to reduce the dosage from seeping back from the vicinity of the orifice to the interior of the ampule holder.

Still a further additional object is to provide a hypo jet injector made in two sections for freedom of action of their respective parts, so that a constant rate of pressure drop may be had as distinguished from erratic pressures caused by binding of the parts, which erratic action makes an injection painful; the injector including a screw and nut opposing a secondary and primary plunger which operationally coact with each other but which are separately supported and guided elements to avoid all possibility of binding.

Other objects are to provide interchange of dosage sleeves for different size ampules; to provide a safety bushing to prevent accidental expulsion of metal parts of the power section if operated when the metering section is disconnected therefrom; and to provide special features of construction for the various parts that coact with each other during operation to minimize all possibility of any binding action occurring during such operation.

With these and other objects in View, my invention consists in the construction, arrangement and combination of the various parts of my hypo jet injector, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings, wherein:

Figure 1 is a full size side elevation of a hypo jet injector embodying my present invention, the injector being placed against the arm of a patient and being held in the hand for operation.

Figure 4a is a detail sectional view on the lines 4a4a shown on both Figures 4 and 16 and showing how the parts are locked after assembly.

Figure 5 is an enlarged sectional view on the line 5-5 of Figure 1, Figure 5 being a continuation of the right hand end of Figure 4 and both figures showing the parts in prepared position and ready to make an injection as illustrated in Figure 1.

Figure 6 is a sectional view of the left end of Figure 4 showing the parts in a different position; to wit, an injector button being depressed for rocking a latch on its pivot and thereby releasing a latch roll so that it, in turn, is permitted to rotate, thus releasing the screw.

Figure 7 is a view similar to the central portion of Figure 5 showing the screw in a farther advanced position than Figure 6, having operated the primary plunger for producing a penetrating jet and the nut about to operate the secondary plunger.

Figure 8 is a sectional view similar to Figure 7 showing the secondary plunger engaged and both the primary and secondary plungers traveling together for producing a follow-through jet.

Figure 9 is a detail sectional view on the line 9--9 of Figure 8.

Figure 10 is a view similar to Figure 8 showing the position of the parts at the end of the injection when a quick cut-elf of the jet has just been effected.

Figure 10a is an enlarged cross section of the nose of the injector shown in Figure 10 to illustrate the coaction of the nose with the epidermis.

Figure 11 is a sectional view showing the first step in a resetting operation which consists of relatching the screw while leaving the nut in the position of Figure 10.

Figure 12 is a similar sectional view showing the power springs being compressed for the next injection operation.

Figure 13 is a sectional view similar to Figure 5 of the dosage sleeve after another filled ampule has been inserted and showing the dosage sleeve being adjusted for decreasing the dose.

Figure 14 is a sectional view similar to portions of Figures 4 and 5 showing the winding sleeve adjusted for reducing the magnitude of the penetrating jet.

Figure 14a is a sectional view similar to a portion of Figure 7 showing the relationship of various parts of the injector and an ampule and follower associated therewith with the winding sleeve adjusted for reducing the magnitude of the penetrating jet and when the injector has operated to the same degree as Figure 7.

Figure 15 is a sectional view similar to Figure 5 showing a smaller ampule and holder substituted for the ampule and holder of Figure 5 to inject a smaller dose of medicament.

Figure 16 is a sectional view through a latch housing and the latch mechanism therein taken on the line 16-416 of Figure 4.

Figure 17 is a sectional view through the winding sleeve showing a ratchet button coacting therewith and taken on the line 1717 of Figure 4.

Figure 18 is a sectional view on the line 18-18 of Figures 4 and 5 showing a dosage button and a dosage sleeve stop for the dosage sleeve.

Figure 19 is a side elevation of a portion of the latch housing and the latch and latch roll associated therewith; and

Figure 20 is a sectional view on the line 2020 of Figure 4 detailing the latch roll and associated parts.

On the accompanying drawings I have used the reference numeral 20 to indicate in general a body for most of the mechanism of my hypo jet injector. The body 20 is exteriorly threaded on its forward end as indicated at 21 and a dosage sleeve is provided with internal threads 31 for coaction with the threads 21.

A winding sleeve 40 is rotatable on the body 20, the sleeve having an inturned flange 41 coacting with an annular shoulder 22 on the body 20 to prevent longitudinal movement in one direction relative to the body. A latch housing 50 is screwed into the rear end of the winding sleeve 40 with a thrust bearing assembly 23 interposed between the body and the latch housing. The thrust bearing assembly comprises washer-like races 24 and balls 25 in a retainer washer 26.

An injector button cap 60 is threaded on the latch housing 50 against a shoulder 51 thereof and the entire assembly of winding sleeve 40, latch housing 50, and injector button cap 60 is held in the assembled relation by drilling into all three of these parts centered at the shoulder 51, tapping the drilled hole and then threading a set screw 42 into the tapped hole as shown in Figure 4a and sealing it in position.

The dosage sleeve 30 has threaded on its forward end an ampule holder 70 adapted to receive an ampule 71 having medicament 72 therein and a cup-like follower 73 formed of a suitable flexible material such as neoprene. The ampule 71 is cylindrical in character and is provided with a reduced discharge nozzle 74 perforated by a minute discharge orifice 75 which is capillary in size such as .002 to .010" in diameter. The ampule holder 70 is covered by a flexible non-slip nose 76 of neoprene.

Having completed the description of the main body forming elements of my hypo jet injector, I will now describe in detail the internal mechanism thereof. A primary plunger 80 is provided consisting of a pin-like rod having a head 81 and a pair of bearing surfaces 82 with a reduced portion between them to minimize the friction in the bore of a secondary plunger. The secondary plunger consists of a sleeve-like portion 91 and a disclike portion 92. The bearing surfaces 82 of the primary plunger 80 slide in the bore of the sleeve 91 and the sleeve itself slides in the bore of the ampule. The periphery of the secondary plunger disc 92 is slightly rounded and slides along the interior surface of the dosage sleeve.

The sleeve-like portion is reduced along its exterior diameter just back of a head-like portion 94 that travels in the ampule. As the secondary plunger travels forward in the dosage sleeve 30, it displaces air therein and to get rid of this air, vent passageways 33 are provided terminating in a relieved annular space between the ampule holder 70 and the dosage sleeve 39. This space is indicated at 34 in Figure 5.

For propelling the secondary plunger 90. I provide a nut and for propelling the primary plunger 80 I provide a screw 110. The nut 100 has a sleeve 101 which is pentagonal in external cross sectional shape to slide in a pentagonal bore 27 (see Figures 17 and 18) of the body 20. The sleeve 101 terminates in a head 102 shown in elevation in Figure 9 which head is provided with five spring seats 103 (see also Figure 10).

The nut 100 and the screw are in turn propelled by five springs 111 seated at one end in the spring seats 103 of the nut as shown in Figure 5 and seated at their other end against a partition 112 at the left end of the body 20, as shown in Figure 4. The partition 112 is provided with five openings 113 therethrough to lighten the body.

The nut 100 has several threads 104 at its left end as shown in Figure 4 which cooperate with the threaded screw 110. At the left end of the pentagonal bore 27, a pair of counterbores are provided indicated at 28 and 29. The counterbore 29 is slightly larger than the counterbore 28 and the counterbore 28 provides a shoulder at the point of transition from the pentagonal bore 27 to the counterbore 28 against which shoulder a safety bushing 107 is positioned, the safety bushing being a press fit in the counterbore 28.

The screw 110 at its left end as shown in Figure 4 has a head 115 provided with a latching shoulder 116. The head 115 terminates in a bifurcated portion which results in a pair of spaced blades 117, the head and the blades being slidable in a square opening 52 of the latch housing 50.

The latch housing 50 is provided with a cross slot 53 in which a latch 54 is pivotally mounted. For this purpose a pivot pin 59 is a press fit in the latch and has its ends rotatable in the latch housing as illustrated in Figure 16. The latch substantially spans the width of the slot 53 and the space between the blades 117 of the screw and is of the shape shown in Figure 4 having a latching shoulder 55 and a spring socket 56. A latch spring 57 has one end mounted in the socket and the other end mounted in an opposing socket 58 of the latch housing 50 for tending to rotate the latch counter-clockwise.

Slidably mounted in the injector button cap 60 is an injector button 61 having a cross bar 62 aflixed thereto and slidable in the slot 53 of the latch housing 50 and the space between the blades 117 of the screw 110. When this button is depressed, as in Figure 6, it rocks the latch 54 against the bias of the spring 57 as shown.

A latch roll 63 is provided having end portions 64 and 65 rotatable in the latch housing (see Figure 20) and a latch portion between the end portions which is of the cross-sectional shape shown in Figure 4 and designated 66. This latch portion is adapted to be engaged by the latching shoulder 55 of the latch 54 and to engage the shoulder 116 of the screw 110 in a particular manner disclosed and claimed in my copending application, hereinbefore mentioned, reference being made in the present specification to Figures 4, 6, 11 and 12 to show the operation without going into detail as to the mechanical merits of the particular latch and latch roll disclosed. It is sufficient to indicate herein that the latch roll 63 is biased to rotate counter-clockwise in Figures 4 and 19 by a latch roll spring 67 wound around a reduced portion 68 of the latch roll and having one end received in a hole 47 therein as shown in section in Figures 19 and 20, and its other end hooked in a hole 46 in the latch housing 50 (as shown in section in Figure 19). The center of rotation of the latch roll being slightly below the lower edge of the shoulder 116 as shown by horizontal and vertical center lines in Figure 4, there is a tendency, as the springs 111 bias the screw 110 toward the right, for the screw to rotate the latch roll clockwise, but it is prevented from doing so by the latch portion 66 engaging the latching shoulder 55 of the latch 54, until such time as the latch is depressed by means of the injector button 61 as in Figure 6. Such an arrangement minimizes the required pressure to operate the latch roll yet provides a rugged holding shoulder against the expanding tendency of the springs 111. The latch shoulder 66 rolls out from under r the screw shoulder 116 when the latch is operated, thus minimizing the wear between the latch roll, the screw shoulder and the latch as distinguished from an ordinary latch which is pulled from beneath a shoulder with the resultant tendency to break down the edges of the latch and shoulder.

For locking the dosage sleeve 30 in various adjusted positions relative to the body 20, I provide a dosage button 35 biased to engage locking teeth 36 formed in an inturned flange 37 at the left end of the dosage sleeve (see lower side of Figure 14). Figure 18 shows the crosssectional shape. The teeth 36 are so formed as to lock the sleeve against rotation in either direction.

To normally prevent removal of the dosage sleeve 30 from the body 20, I provide a dosage sleeve stop 38 (see upper side of Figure 14). The cross-sectional shape is such as to prevent engagement with the locking teeth 36 as shown in Figure 18, the dosage sleeve stop 38 having a shoulder 39 to be engaged by the flange 37 at the outer limit of movement of the dosage sleeve. At such outer limit of movement which would be about one thread farther than the illustrated position in Figure 4, the left end of the button is exposed so that it can be depressed for permitting removal of the dosage sleeve as when it is de sirable to replace it with another one such as a shorter sleeve as shown in Figure 15 as compared with Figure 5.

I provide a ratcheting means for the winding sleeve 40 as illustrated in Figures 14 and 17 to prevent the sleeve from unwinding under the action of the springs 111 after they have been compressed. This sleeve, at its right hand end in Figure 4, is provided with a stop flange 41 as already described coacting with the shoulder 22. This flange is provided With ratchet teeth 43 cut into the flange 41 with which a tooth of a ratchet button 44 is adapted to coact. The ratchet button 44 permits clockwise rotation of the winding sleeve 40 but locks it against counter-clockwise rotation except when the ratchet button is depressed, the button extending forwardly (to the right) from the flange 41 having the teeth 43 therein as shown in Figure 14 so that it is exposed beyond the flange and can thereby be engaged for depression at the will of the operator. The ratchet button as well as the dosage button 35 and the dosage sleeve stop 38 are biased outwardly from the axis of the injector as illustrated by means of springs seated in sockets of the body and the buttons.

Practical operation In the operation of my hypo jet injector I will start with the assumptions that the parts are in the position of Figures 4 and 5, the ampule 71 is in place for an injection of the medicament 72 therein and the springs 111 are latched in their compressed condition and ready for release. The injector is then held in the hand illustrated at 126 in Figure 1 and placed against an arm or the like 121 of the patient with the resilient nose 76 pressed firmly against the arm as shown in Figure 10a. The end of the resilient nose bears tightly against the discharge nozzle 74 of the ampule and both the nose and the nozzle depress the epidermis 122 as shown diagrammatically.

This efiects a tight seal between the discharge orifice 75 and the epidermis to prevent the escape of medicament at this point along the outer surface of the nose 76 and seepage along the nozzle 74 and into the holder 70. Any escape of liquid at the skin surface may cause the injector to slip or skid thus resulting in a painful multiple injection but with proper pressure as indicated in Figures 1 and 10a there is no possibility of this happening. Instead, a tight seal is had between the edge of the orifice '75 and the epidermis to insure that all the medicament discharged from the ampule will first, at high pressure, open a channel through the epidermis and the underlying tissues and thereafter, at a lower follow-through pressure, flow into such channel for lateral dispersion from its bottom as fully disclosed in my copending applications above referred to.

It will be noted in Figure 1 that the thumb of the hand 120 is placed on the injector button 61 so that after the proper pressure of the injector against the arm 121, the button can be depressed by the thumb as to the position shown in Figure 6. As soon as the latch shoulder 55 of the latch 54 disengages the latching portion 66 of the latch roll, the compressed springs 111 pulling on the screw 110 will cause the latch roll to rotate clockwise as illustrated and when it reaches the dotted position, the shoulder 116 will pass by the latch roll thus permitting the nut 100 and the screw 110 to be propelled downwardly in the instrument.

First of all, the screw will engage the head 81 of the primary plunger with impact due to spacing between the two as shown in Figure 5 and the forward end of the primary plunger will engage and distort the follower 73 to the position shown in Figure 7 which effects discharge of the medicament 72 as a penetrating jet 79 through the orifice 75 and into the arm 121 under relatively high pressure such as 10,000 p. s. i. as illustrated in Figure 10a. This relatively high pressure produces a high velocity jet that penetrates to a predetermined depth in the tissues of the arm and after that a fo11ow-through pressure is produced by reason of the nut engaging the disc 92 of the secondary plunger 91 and propelling it forwardly simultaneously with the primary plunger. In Figure 7 the nut has almost reached the disc 92 and the dotted position of the screw in Figure 6 corresponds to Figure 7. Fundamentally, the two pressure steps are achieved by causing the driving force to act first on a hydraulic piston of small cross-sectional area and then on a hydraulic piston of larger area (the primary area plus the secondary area); pressure being expressed by force divided by piston area.

Referring to Figure 8, the nut has reached the disc and has propelled the secondary plunger some distance beyond that shown in Figure 7 so that the lower pressure follow-through jet '77 is entering the channel already formed by the penetrating jet and since the area now worked upon is represented by both plungers 83 and 91 as distinguished from the plunger 80 only, the followthrough jet is at much lower pressure (for instance about 3000 p. s. i.).

The follow-through jet continues until all the medicament is injected and the primary plunger reaches the position shown in Figure 10, squeezing the follower 73 againstand into the nozzle 74 of the ampule 71 to effect a quick cut-off of flow.

fter the injection has been completed, in order to make another one, it is necessary to rewind the springs 111, discard the ampule from which the medicament has been discharged and insert another one. These opera tions are accomplished in the following manner.

Referring to Figure 11, the first operation is to relatch the screw 110 on the latch roll 63 and lock the roll by means of the latch 54. This is accomplished by holding the ratchet button 44 depressed and rotating the winding sleeve 40 counter-clockwise by one hand while holding the body 20 in the other hand, the thumb or a finger of said other hand being used to depress the button 44. The sleeve is rotated counter-clockwise as far as possible as shown in Figure 11 which causes the screw to be screwed backwardly with relation to the nut, the nut remaining in the same position as shown in Figure 10. It willl be noted however that in Figure 11 the springs 111 are still expanded but the screw has been shifted rearwardly (to the left) until the shoulder 116 of the head 115 of the screw has passed the latching portion 66 of the latch roll thus permitting the roll to be rotated counter-clockwise to the position illustrated under the bias of the latch roll spring 67 and stopped against rotation by engaging the reduced shank of the screw. As soon as the latching edge of the portion 66 has rotated past the latching shoulder 55 of the latch 54, the latch spring 57 will throw the latch to the position illustrated producing a distinct click whereupon the rotation of the winding sleeve 40 may be stopped although if rotation is continued, it will shortly thereafter be stopped by the end of the head 115 between the blades 117 of the screw engaging the latch 54 as will be obvious by inspecting Figure 4.

Thereafter the springs 111 may be compressed by rotating the winding sleeve 49 clockwise with the ratchet button 44 released and therefore operative so that ratcheting occurs but reverse rotation is prevented. The first portion of the clockwise rotation will screw the screw 110 back into the nut 1&0 until the shoulder 116 of the screw engages the latch roll portion 66 and rotates the latch roll clockwise from the position of Figure 11 to the position of Figure 4. Thereafter, further rotation of the winding sleeve produces compression of the springs 111 because the screw is held by the latch roll against forward movement and since the screw is rotating, the nut will be pulled back along its threads.

Rotation is continued until the head 102 of the nut engages a shoulder 130 of the body 20 as shown in Figure 5, the spring seats 103 traveling between five posts 131 (see Figures and 9) of the body' 20, the forward ends of which posts serve as stops for the secondary plunger disc 92. The springs 111 are now fully compressed and the power section of the injector ready for operation. The springs at this time exert considerable pressure such as approximately 315 lbs. aggregate. In the discharged position of Figure 10 they still exert about one-third that pressure, the springs being preloaded during assembly of the injector to approximately 105 lbs. aggregate. The purpose of the preloading is to maintain a reasonably high pressure throughout the whole stroke right up to the instant the injection ends so that the last of the injection occurs at about 1000 p. s. i. Thus effective completion of the follow-through jet occurs whereas any considerable decrease in liquid pressure would result in the last portion of the medicament being at such low pressure that it would not follow-through as required.

After the springs 111 have been latched in their tensioned condition as in Figures 4 and 5, the power section is ready for operation and it remains to discard the discharged ampule of Figure 10 and insert a new one. This is accomplished by unscrewing the ampule holder 70 from the dosage sleeve 30 and permitting the discharged ampule to be dropped out of the dosage sleeve. A new am le is removed from its enclosing jacket as disclosed in my copending patent application, Serial No. 93,281, filed May 14, 1949, now Patent 2,645,328, which keeps it sterile until ready for use, and is dropped from the jacket into the bore 32 of the holder. The ampule holder 70 is then screwed back in position as in Figure 5 and the injector is ready for the next injection.

The metering section of my hypo jet injector is constructed as described for dosage adjustment as illustrated in Figure 13. Thus far I have described use of the instrument for injecting a maximum dose, that is, the full contents of the ampule 71 illustrated. The particular ampule disclosed is a 1 cc. size though of course the instrument can be designed for larger doses. However, if part of the medicament is discharged before the injection is made, then the injection will be only of the remaining part of the dose.

Dosage adjustment is accomplished by depressing the dosage button 35 so that the dosage sleeve 30 can be rotated in a direction onto the body 30 as from the position of Figure 5 to the osition of Figure 13. In doing this, the ampule is propelled backwardly over the primary and secondary plungers so that it is likewise propelled backwardly over the follower 73 which is held against movement by the plungers. Some of the medicament is thereby squirted out as iliustrated at 7 3.

As illustrated in Figure 1, the upper end of the dosage sleeve may he graduated in twelfths of a rotation to get various portions of 0.1 cc. such as A /6, A, /3, /2, 1 /3, A, or The dosage sleeve can then be adjusted about four and one-half turns thus setting a range from .55 cc. to 1 cc., the .9 cc. adjustment being shown in Figure 13.

The magnitude of the penetrating jet 79 in proportion to the magnitude of the follow-through jet 77 can be adjusted. in Figures 4 to 10, maximum pressure for the penetrating jet has been illustrated represented by the distance of travel of the nut in Figure 5 before it engages the secondary plunger disc 92 (a position assumed immediately following that shown in Figure 7). In Figure 14 I show a shorter travel of the nut 100 before it strikes the disc 2 and this is accomplished by depressing the ratchet button 44 and rotating the winding sleeve 40 backwards (counter-clockwise) as much as two and onehalf turns. Indicia such as A, B, C, D, and E are provided on the winding sleeve for dividing it into five equal circumferential spaces. Only the A is shown in Figure 1. Each space represents a drop-off of pre-travel of the nut and a proportionally shorter stroke of the primary plunger before the nut strikes the secondary plunger, the travel of the primary plunger being thus limited beyond the front end of the secondary plunger in the first stage of the injection. Referring to Figure 14a, a reduction in .9 primary plunger travel is obvious when comparing this figure with Figure 7, the pre-travel of the nut 100 being reduced according to Figure l4 but the nut almost contacting the secondary plunger as in Figure 7.

A suitable chart can be furnished the physician for indicating which of the indicia the winding sleeve should be adjusted to and in which turn of the two and one-half turns in order to get an injection to the proper depth in various types of tissues such as those of adults and chil dren, light and heavy skinned persons, various parts of the body, and depending on whether the injection is to be intra-fascial or muscular, etc. Thus the depth to which the penetrating jet goes can be nicely regulated in addition to dosage being adjustable as already referred to.

A further feature for dosage adjustment consists of providing a dosage sleeve 30 as shown in Figure 15 modified by different dimensions to take a shorter ampule 71a, and the length of the sleeve being shortened accordingly so that there is less room for travel of the primary and secondary plungers. The sleeve 30a is likewise graduated in twelfths to represent anywhere from-.05 cc. to .5 cc., these values being minimum and maximum dosage for the ampule 71a.

Summarizing the operation of my hypo jet injector, when ready for a jet injection, the injector button is pressed. After the injection, the screw is relatched by counter-clockwise rotation of the winding sleeve and the springs 111 are then tensioned by clockwise rotation of the winding sleeve. The discharged ampule is then replaced with a filled one and the injector is ready for performing another injection.

The dosage in the ampule may be reduced if desired by rotary adjustment of the dosage sleeve. The effective stroke of the primary plunger before the stroke of the secondary plunger begins may be reduced to control the depth to which the penetrating jet pierces, by merely backing off the winding sleeve (rotating it counter-clock wise the desired degrees).

From the foregoing description, it will be obvious that I have provided a hypo jet injector in which moderate spring force may be utilized for producing the high pressures necessary for a penetrating jet with reduced pressure (after the penetrating jet has performed its function) for causing a follow-through jet to merely feed the medicament into the channel that was opened by the penetrating jet, all of which operations may be nicely controlled.

Considerable leverage is had in loading the springs 111 by means of the screw threaded connection between the nut and the screw, the screw being rotated by the winding sleeve 40 which has sufiicient diameter as obvious from Figure 1 for a good hand grip thereon during the winding operation. The springs are latched in the compressed condition by an efficient latch roll and latch arrangement which operates with a minimum of wear so that it is capable of proper operation for many thousands of cycles without break-down of the latching edges as in many types of latching devices.

In addition to providing a primary and secondary plunger arrangement that produces a high penetrating jet pressure and a lower follow-through jet pressure, the arrangement is such that the primary plunger effects a quick cut-01f of the medicament as shown in Figure with a minimum of the medicament left in the ampule.

The ampule holder 70 and the bore 32 of the dosage sleeve 30 provide thick metal backing for the ampule which is formed of relatively light sheet metal. It is therefore practical with an injector of the construction disclosed to use thin metal ampules even though great pressures are involved. The nozzle 74 of the ampule being somewhat smaller in diameter is subjected to less total pressure force and therefore need not be supported. If a defective ampule breaks at this point, the primary and secondary plungers can travel farther but will be stopped by a resilient washer 132 in'the dosage sleeve '30.

The injector is made in two sections for freedom ofaction, the metering section with the primary and secondary plungers therein being separate from the power section having the screw and the nut therein. When thetwo sections are associated together by screwing the dosage sleeve 36 on the body 20, the parts are in position:

for the primary and secondary plungers to be operatively engaged by the screw and the nut respectively upon release of the stored-up energy in the springs 111. By merely providing an engagement connection, all possibility of binding of the parts in operation is eliminated.

To further aid in this respect, the engagement is at or' Referring: to Figure 5, it will be noted that the right hand end of the screw is reduced to engage a rounded surface of theconcentrically around the axis of the plungers.

primary plunger head 81 for engagement substantially at the center line, and the forward end of the nut is provided with the annular boss 105 surrounding the primary plunger to engage the secondary plunger disc 92 adjacent its center instead of around its outside edge. Also the rounding of the outer edge of the secondary plunger disc 92 and its being guided in the body while the head 94 is guided in the ampule only, eliminate any binding that might result from misalignment of the ampule rela tive to the body.

There is illustrated a slight space between the screw and the primary plunger head 81 for producing impact which aids in the starting of the penetrating jet as the screw and the nut can thereby gain momentum after release of the screw at the latch roll. Accordingly, the time for building up pressure from atmospheric to maximum for the penetrating jet is reduced to a minimum. The space above referred to may occur instead between the primary plunger and the follower 73 as the plunger floats freely in the bore of the secondary plunger.

To avoid any peening trouble where the screw engages the primary plunger, the bore of the nut is slightly tapered as shown at 1% in Figure 5 and where the annular boss 105 strikes the disc 92 of the secondary plunger the disc is counter-bored as at 93.

The vent passageways 33 in the dosage sleeve 39 permit escape of air ahead of the secondary plunger disc 92 so that the desired quick action of the springs 111 is not hampered by compressed air in the chamber of the dosage sleeve ahead of the disc. The passageways 33 open into the annular space 34 for dischar e to atmosphere in a lateral direction instead of toward the patient during the injecting operation.

Referring to Figure 4, it will be noted that the injector button 61 is slightly countersunk with relation to the upper end of the instrument represented by the injector button cap 6%. This is so that in the Wound position of the injector it will not be accidentally discharged if set on a table or other surface with the injector button-enddown.

To avoid accidental discharge of the assembly of the screw, the nut and the five springs 111 from the power section when the metering section is disconnected therefrom, I provide the safety bushing 107 against the shoulder of the counter-bore 28. The shoulder 116 of the screw in normal operation does not engage the safety bushing as it is stopped before it does so by the primary plunger in the position of Figure 10 or if the nozzle of the ampule fails, then in a slightly farther advanced position the secondary plunger disc 92 engages the resilient washer 132. With the dosage sleeve 30 removed however (the primary and secondary plungers being carried by it) there is nothing to stop the travelof the nut and the screw except the safety bushing 107. Thus I prevent accidental discharge of the parts RM, 119 and 111 from the power section if the injector button is depressed while the dosage sleeve is off the instrument.

In the event it is desirable to not perform an injection after the injector has been prepared for operation, the compression of the springs 1 t can be relieved by pressing the ratchet button 414 and rotating the winding sleeve 49 counter-clockwise or permitting it to be rotated. by the springs and thus the springs expand until stopped by the disc 92 engaging the washer 132 if there is no ampule in the holder or stopped as in Figure if an ampule is held in the holder.

Some changes may be made in the construction and arrangement of the parts of my hypo jet injector without departing from the real spirit and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim as my invention:

1. In a hypo jet injector, an assembly comprising an elongated body, an ampule holder detachably connected with one end thereof and adapted to hold an ampule having liquid and a follower therein, the ampule having a discharge orifice for the liquid, a plunger slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule through the discharge orifice thereof, and means for propelling said plunger comprising a nut slidably and non-rotatably mounted in said body, a plurality of power springs arranged longitudinally in said body and interposed between the body and said nut, a screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement relative thereto, and a winding sleeve rotata'bly mounted on said body for rotating said screw relative to said nut.

2. In a hypo jet injector, an assembly comprising a body, means adapted for holding an' ampule in said body having liquid and a follower therein, the ampule having a discharge orifice for the liquid, at plunger mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule through the discharge orifice thereof, and means for propelling said plunger comprising a nut slidably and non-rotatably mounted in said body, spring means arranged longitudinally in said body and interposed between the body and said nut, a screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement relative thereto, and a winding sleeve rotatably mounted on said body and having a slidable and non-rotatable connection with said screw.

3. In a hypo jet injector, an assembly comprising a body, means adapted for holding an ampule in said body having liquid and a follower therein, the ampule having a discharge orifice for the liquid, a plunger mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule through the discharge orifice thereof, and means for propelling said plunger comprising a nut slidably mounted in said body, a plurality of power springs interposed between the body and said nut, screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement relative thereto, and means rotatably mounted on said body for rotating said screw relative to said nut to latch the same when rotated in one direction and to'compress said power springs when said means is thereafter rotated in the opposite direction.

4. In a hypo jet injector, an assembly comprising a body and adapted to receive and hold an ampule containing liquid to be injected and a follower behind the liquid, primary and secondary plungers mounted in said body and slidable relative thereto and adapted for engaging and propelling the follower to discharge the liquid from the ampule at two different sequential pressures, and means in said body for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs in said body surrounding said nut and interposed between it and the body, a screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement, a manually engageable element on said body for rotating said screw relative to said nut, said element being constrained against longitudinalmovement relative to said body and said screw being slid'able and non-rotatable relative to said element,

5. In a hypo jet injector, an assembly comprising an elongated body, an ampule holder thereon adapted for holding an ampule containing liquid to be injected and a. follower behind the liquid, primary and secondary plungers slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule at an initial high primary pressure and a lower secondary pressure, and means in said body for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, spring means interposed between it and the body, a screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement relative thereto, and a manually engage'able' element on said body for rotating said screw relative to said nut, said screw being slidable and nonrotatable relative to said element.

6. In a hypo jet injector, an assembly comprising a body, means at one end thereof adapted for containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the means in a high primary pressure stage and a lower secondary pressure stage, and means in said body for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs surrounding said nut and interposed between it and the body, a screw in said body and threaded in said nut, releasable means in said body for engaging and latching said screw against longitudinal movement relative thereto, and a rotatable winding sleeve on said body for rotating said screw relative to said nut, said releasable means being rotatable with said winding sleeve.

7. A hypo jet injector of the character disclosed comprising an elongated body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, a plunger adapted for moving the follower, and means for engaging and propelling said plunger for causing the follower to discharge the medicament from the means for containing it comprising a nut slidably and non-rotatably mounted in said body, spring means in said body constraining said nut to move toward said plunger, a'screw in said body for retracting said nut, means of operative connection between said plunger and said screw, a latch housing rotatable against the opposite end of said body, ascrew in said body and threaded in said nut, and slidably and non-rotatably mounted in said latch housing, said screw having a latched shoulder, a latch in said latch housing therefor, and a second latch in'said latch housing'for releasing the first latch.

8. In a hypo jet injector of the character disclosed, a body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, n plunger adapted for moving the follower, and means for engagingand propelling said plunger for causing the follower to discharge the medicament from the means for containing it comprising a nut slidably and non- 13 v rotatably mounted in said body, spring means constraining said nut to move toward said plunger, a screw in said body for retracting said nut, means of engagement between said plunger and said screw, a latch housing rotatable against the opposite end of said body, a screw mounted in said body and threaded in said nut, and slidably and non-rotatably mounted in said latch housing, said screw having a latching shoulder, a latch in said latch housing therefore, means in said latch housing for releasing said latch, and means exterior of said body for rotating said latch housing relative to said body.

9. In a hypo jet injector, a body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, a plunger adapted for moving the follower, and means for actuating said plunger for causing said follower to discharge the medicament from the means containing it comprising a nut slidably mounted in said body, pre-loaded spring means in said body constraining said nut to move toward said plunger, a screw in said body for retracting said nut, a latch housing rotatably mounted on said body, a screw threaded in said nut and slidable and non-rotatable in said latch housing, said screw having a latching shoulder, a primary latch therefor, a secondary latch for releasing said primary latch, said latches being carried by said latch housing, and a sleeve rotatable on said body and connected with said latch housing for rotating it.

10. A hypo jet injector comprising an elongated body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, a primary plunger and a tubular secondary plunger adapted for moving the follower, and means for propelling said plungers to engage said follower comprising a nut and a screw, said nut being non-rotatably mounted in said body, said screw being rotatably mounted in said body and threaded in said nut, spring means in said body constraining said nut and screw to move toward said plungers, a latch housing rotatably carried by said body, said screw being slidable and non-rotatable therein, latching means carried by said latch housing for latching said screw against longitudinal movement relative to said latch housing and said body, and manually operable means extending outside said body for releasing said latching means.

11. A hypo jet injector comprising a body, means supported on said body and adapted for containing a medicament and a follower behind the medicament, a primary plunger, a tubular secondary plunger surrounding said primary plunger, said plungers being adapted to propel the follower, and means for propelling said plungers comprising a nut and a screw, said nut being non-rotatably mounted in said body and adapted to engage said secondary plunger, said screw being rotatably mounted in said body, threaded in said nut and adapted to engage said primary plunger ahead of said nut engaging said secondary plunger, spring means in said body constraining said nut and screw to move toward said plungers, a latch housing rotatable on said body, said screw being slidable and non-rotatable therein, latching means carried by said latch housing for latching said screw against longitudinal movement relative to said latch housing and said body, and manually operable means carried by said latch housing for releasing said latching means.

12. A hypo jet injector comprising an elongated body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, a primary plunger adapted for moving the follower, a secondary plunger, and means for propelling said plungers to sequentially engage said follower comprising a nut and a screw, said nut being non-rotatably mounted in said body, said screw being rotatably mounted in said body and threaded in said nut, spring means in said body constraining said nut to move toward said plungers, a latch housing rotatable at the opposite end of said body, said screw being slidable and non-rotatable therein, latching means carried by said latch housing for latching said s s 14 screw against longitudinal movement relative to said latch housing. and said body, manually operable means in said latch housing for releasing said latching means, and a sleeve on said body for rotating said latch housing.

13. A hypo jet injector comprising a body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, a primary plunger adapted for coacting with the follower over a portion of its cross-sectional area, a secondary plunger adapted for coacting with the remainder of the cross-sectional area of the follower, and means for propelling said plungers to sequentially engage the follower comprising a nut and a screw, said nut being non-rotatably mounted in said body, said screw being rotatably mounted in said body and threaded in said nut, spring means in said body constraining said nut to move toward said plungers, a latch housing rotatable at the opposite end of said body, said screw being slidably and non-rotatably mounted therein, latching means carried by said latch housing for latching said screw against longitudinal movement relative to said latch housing and said body, manually operable means in said latch housing for releasing said latching means, and a sleeve on said body for rotating said latch housmg.

14. A hypo jet injector comprising a body, means at one end thereof adapted for containing a medicament and a follower behind the medicament, plunger means adapted for acting first on a small area of the follower to produce a high hydraulic pressure and then on the entire follower area to produce a lower hydraulic pressure, and means for sequentially engaging said plunger means comprising a nut and a screw, said nut being nonrotatably mounted in said body, said screw being rotatably mounted in said body and threaded in said nut, spring means in said body constraining said nut to move toward said plungers, a latch housing rotatable at the opposite end of said body, said screw being slidable and non-rotatable therein, latching means carried by said latch housing for latching said screw against longitudinal movement relative to said latch housing and said body, means for releasing said latching means, and a sleeve on said body for rotating said latch housing.

15. A hypo jet injector comprising a body, a dosage sleeve thereon, an ampule holder detachably connected with said dosage sleeve and adapted to receive an ampule having a discharge orifice for liquid, the ampule having liquid and a follower therein, a plunger adapted for moving the follower, said plunger being slidably mounted in said body, and means for propelling said plunger comprising power means carried by said body and consisting of a nut element and a screw element relatively threaded to each other, springs in said body interposed between it and said nut, means for rotating one of said elements while holding the other against rotation for compressing said springs, and latching means on said body for said screw, said latching means being releasable for permitting expansion of said springs.

16. A hypo jet injector comprising a body, an ampule holder detachably connected therewith and adapted to receive an ampule having a discharge orifice for liquid, the ampule having liquid and a follower therein, plunger means adapted for moving the follower, said plunger means being slidably mounted in said body, and means for propelling said plunger means comprising power means carried in said body and consisting of a nut and a screw relatively threaded to each other, means for rotating one while holding the other against rotation, springs in said body interposed between the body and said nut and compressed by the relative rotation of said nut and screw, and latching means on said body for said screw, said latching means being releasable for permitting expansion of said springs.

17. In a hypo jet injector, a body, means at one end thereof adapted for containing liquid to be injected and .a follower behind the liquid, primary and secondary Pl P WS slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule at two different sequential pressures, said secondary plunger being of tubular character and surrounding said primary plunger, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs arranged around said nut and interposed between it and the body, said nut having a ring-like boss surrounding said primary plunger for engaging said secondary plunger, a screw mounted in said body, threaded in said nut and adapted to engage said primary plunger, releasable means in said body for latching said screw against longitudinal movement, and a winding sleeve rotatable on said body and connected with said screw for rotating the same, said screw being slidable and non-rotatable relative to said winding sleeve.

18. In a hypo jet injector, a body, an ampule holder adapted to hold an ampule at one end thereof for containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidably mounted in said body for engaging and propelling the follower to discharge the liquid from the ampule at two diiferent sequential pressures, said secondary plunger being of tubular character, surrounding said primary plunger and having a disc portion cooperating with the bore of said body to constitute a guide for said plungers, power means in said body for propelling said primary and secondary plungers, vent passageways in said body for permitting escape of air ahead of said secondary plunger and its disc portion, said ampule holder and said body having an annular space therebetween into which said passageways discharge.

19. In a hypo jet injector, power means adapted for effecting an injection from a container having liquid and a liquid follower therein, a dual plunger system driven by said power means with the force of the power means adapted to act first on one plunger coacting with a part only of the follower area and then adapted to act on both plungers against the entire follower area, means on said injector for adjusting the volume displaced by the first plunger before the second plunger takes effect, and independent adjustment means on said injector for regulating the total displacement of the two plungers.

20. In a hypo jet injector, an elongated body, an ampule holder adapted for holding an ampule containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidable in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule at two diiferent sequential pressures, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs interposed between it and the body, a screw threaded in said nut, releasable means on said body for latching said screw against longitudinal movement relative thereto, and a winding sleeve rotatable on said body and connected with said screw for rotating the same, said screw being slidably and non-rotatably mounted in said winding sleeve, vent passageways in said body for permitting escape of air ahead of said secondary plunger and its disc portion, and an annular space between said ampule holder and said body into which said passageways discharge, said ampule having a reduced nozzle into which the follower is adapted to be crowded with portions of the follower substantially filling the nozzle at the end of the injection operation for effecting quick cut-off of the jet issuing from said ampule with minimum residual liquid in the ampule.

7.1. in a hypo jet injector, a body, means at one end thereof adapted for containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule at two different sequential pressures, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs arranged around said nut and interposed between it and the body, a screw threaded in said nut, releasable means on said body for latching said screw against longitudinal movement relative thereto, a winding sleeve rotatable on said body and connected with said screw for rotating the same, said screw being slidably and non-rotatably mounted in said winding sleeve, and a cushioning element in said body for said secondary plunger slightly beyond the normal discharge limit thereof.

22. In a hypo jet injector, a body, a dosage sleeve thereon, an ampule holder associated with said dosage sleeve and adapted for holding an orificed ampule having liquid and a follower therein, plunger means adapted for engaging the follower to propel it with relation to the ampule for discharging the liquid from the ampule, said dosage sleeve being threaded on said body to predischarge a portion of the liquid by predetermined rotation of said dosage sleeve before injection, a dosage button carried by said body and engaging teeth of said dosage sleeve to normally prevent rotation thereof, said dosage button being depressiblc to permit such rotation, said dosage button being elongated to coact with said sleeve and lock it against rotation in all positions of adjustment thereof, and means for propelling said plunger means comprising power means carried in said body and consisting of a nut and a screw relatively threaded to each other, means for rotating one while holding the other against rotation, springs in said body interposed between it and said nut, and latching means on said body for said screw, said latching means being releasable for permitting expansion of said springs.

23. In a hypo jet injector, a body, a dosage sleeve thereon, an ampule holder associated with said dosage sleeve and adapted for holding an ampule having liquid and a follower therein, plunger means adapted for engaging the follower to propel it with relation to the ampule for discharging the liquid from the ampule, said dosage sleeve being threaded on said body to predischarge a portion of the liquid by predetermined rotation of said dosage sleeve prior to injection, and means in said body for propelling said plunger means comprising a nut and a screw relatively threaded to each other, means for rotating one while holding the other against rotation, springs in said body interposed between it an said nut, and latching means on said body for said screw, said latching means being releasable for permitting expansion of said springs.

24. In a hypo jet injector, a body, a dosage sleeve thereon, an ampule holder associated with said dosage sleeve and adapted for holding an ampule having liquid and a follower therein, plunger means adapted for engaging the follower to propel it with relation to the ampule for discharging the liquid from the ampule, said dosage sleeve being threaded on said body to predischarge a portion of the liquid by predetermined rotation of said dosage sleeve prior to injection, and means for propelling said plungers comprising power means consisting of a nut and a screw in said body and relatively threaded to each other, a winding sleeve on said body for rotating one while holding the other against rotation, springs interposed between said body and said nut, and latching means on said body for said screw, said latching means being releasable for permitting expansion of said springs.

25. In a hypo jet injector, a body, a dosage sleeve threaded thereon, an ampule holder associated with said dosage sleeve and adapted for holding an ampule having liquid and a follower therein, plungers adapted for engaging the follower to propel it with relation to the ampule for discharging the liquid from the ampule, a dosage button on said body engaging teeth of said dosage sleeve to normally prevent rotation thereof relative to said body,

masters a dosage sleeve lock on" said body having a shoulder to prevent removal of said dosage sleeve, said shoulder coactingwith an inturned flange of the dosage sleeve and the dosage sleeve lock being exposed for unlocking at the outer limit of adjustment of the dosage sleeve, and means for propelling said plungers comprising power means carried in'said body, said power'means' comprising a spring system for energy storage, a spring loading means and a spring energy release means.

26. In a hypo jet injector, an elongated body, means at one end thereof adapted for containin'g'liq'uid to be injected and a follower behind the liquid, primary and secondary plungers slidably'mounted in said body and adapted forengaging and propelling the follower to discharge the liquid' from the ampule at two different sequential pressures, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, said nut and interposed between it and the body, ascrew in said body and threaded in said nut, releasable means on said body for latching said screw against longitudinal movement, a winding sleeve on said body, rotatable in one direction relative thereto and connected with said screw for rotating the same, said screw being slidably and non-rotatably mounted in said winding sleeve, said winding sleeve having ratchet teeth, a ratchet button on said body therefor to permit rotation of the winding sleeve in a direction for compressing said power springs and preventing rotation thereof in the opposite direction except when said ratchet button is depressed, such rotation thereof in the opposite direction effecting a reduction of the travel of said primary plunger before said secondary plunger is propelled simultaneously with said primary plunger.

27. In a hypo jet injector, an elongated body, means at one end thereof adapted for containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the means at two different sequential pressures, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs arranged around said nut and interposed between it and the body, a screw mounted in said body and threaded in said nut, releasable means on said body for latching said screw against longitudinal movement, a winding sleeve rotatable on said body in one direction and connected with said screw for rotating the same, said screw being slidably and non-rotatably mounted in said winding sleeve, said winding sleeve being rotatable on said body in an opposite direction after said rotation thereof for compressing said springs to change the relative initial position of said nut with respect to said screw.

28. In a hypo jet injector, an elongated body, means at one end thereof adapted for containing liquid to be injected and a follower behind the liquid, primary and secondary plungers slidably mounted in said body and adapted for engaging and propelling said follower to discharge the liquid from the means at two different sequential pressures, means for propelling said primary and secondary plungers comprising a nut slidably mounted in said body, a plurality of power springs arranged around said nut and interposed between it and the body, a screw mounted in said body and threaded in said nut, releasable means on said body for latching said screw against longitudinal movement, a winding sleeve rotatable on said body in one direction therearound and connected with said screw for rotating the same, said screw being slidably and non-rotatably mounted in said winding sleeve, said winding sleeve being rotatable on said body in an opposite direction therearound after said rotation thereof for compressing said springs to first change the relative initial position of said nut with respect to said screw and therea plurality of power springs arranged around after change the position of said secondary plunger relative to said primary plunger.

29. In a hypo jet injector, a body, an ampule holder detachably connected with one end thereof and adapted to hold an orificed ampule having liquid and a follower therein, said holder and said body having a bore adapted to receive and support the ampule against explosion and a resilient nose covering said ampule holder and having a portion adapted for extending around the nozzle of the ampule, a plunger slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule through the orifice thereof, and means for propelling said plunger comprising a nut slidably and non-rotatably mounted in said body, a plurality of power springs arranged longitudinally in said body and interposed between the body and said nut, a screw in said body threaded in said nut, releasable means on said body for latching said screw against longitudinal movement, and a winding sleeve rotatable on the other end of said body for rotating said screw relative to said nut.

30. In a hypo jet injector, a body, an ampule holder detachably connected with one end thereof and adapted to hold an orificed ainp'ule having liquid and follower therein, said holder and said body having a bore adapted to receive and supportthe ampule against lateral expansion, a plunger slidably mounted in said body and adapted for engaging and propelling the follower to discharge the liquid from the ampule through the orifice thereof, and means for propelling said plunger comprising a nut slidably and non-rotatably mounted in said body, a plurality of power springs arranged longitudinally in said body and interposed between the body and said nut, a screw in said body and threaded in said nut, releasable means on said body for latching said screw against longitudinal movement relative thereto, and a winding sleeve rotatable on the other end of said body for rotating said screw relative to said nut.

31. In a hypo jet injector, power means in said injector adapted for effecting an injection from a container having liquid and a liquid follower therein, a dual plunger system in said injector driven by said power means with the force of the power means acting first on one plunger adapted for coacting with a part only of the follower area and then acting on both plungers and thereby adapted for coacting against the entire follower area, and means in said injector for adjusting the volume displaced by the first plunger before the second plunger takes effect.

32. In a hypo jet injector, power means in said injector adapted for effecting an injection from a container having liquid and a liquid follower therein, a plunger system in said injector driven by said power means with the force of the power means adapted to act on and thereby propel the follower, a dosage sleeve on said injector for the container and movable axially in respect to said plunger system said container being conn cted with said dosage sleeve to be moved therewith axially of said plunger system to thereby predischarge a portion of the liquid from the container, and means for locking said dosage sleeve against said movement in respect to said plunger system.

33. In a hypo jet injector, a body, a dosage sleeve thereon, an ampule holder associated with said dosage sleeve and adapted for holding an orificed ampule having liquid and a follower therein, power means in said body for moving the follower, a plunger system driven by said power means with the force of the power means adapted to act on said follower, said dosage sleeve being movable on said body axially of said plunger system and operatively connected with said ampule holder to simultaneously move it also axially of said plunger system to predischarge a portion of the liquid before the injecting operation.

34. In a hypo jet injector, power means in the injector adapted for effecting an injection from a container having liquid and a liquid follower therein, a dual plunger system in said injector driven by said power means with the force of the power means adapted to act first on one plunger coacting with a part only of the follower area, and then on both plungers against the entire follower area, manual release means in said injector for said power means to suddenly release the energy stored therein to efiect the injection, means on said injector for adjusting the volume displaced by the first plunger before the second plunger takes effect, and independent means on said injector for adjusting the total displacement of the two plungers.

35. In a hypo jet injector, power means in said injector adapted for effecting an injection from a container having liquid and a liquid follower therein, manual means in said injector for gradually bringing said power means from a partially discharged condition to a charged condition, a dual plunger system in said injector driven by said power means with the force of the power means adapted to act first on one plunger coacting with a part only of the follower area and then on both plungers against the entire follower area, a manual release member in said injector to suddenly release the energy stored in the power means to effect the injection, and means on said injector for adjusting the volume displaced by the first plunger before the second plunger takes effect.

36. A hypodermic injection apparatus including in combination a hollow body providing adjacent one of its ends a space to receive a medicament-containing ampule from which liquid is to be discharged at high velocity, a loading cap movably mounted by said body to close said space, a compressible pressure accumulator disposed within said body and operatively connected to said space to act on an ampule contained therein, manually operated force-compounding means carried by said body for compressing said accumulator, means for retaining said accumulator in compressed condition and manually shiftable means accessible on the exterior of said body to release said retaining means.

References Cited in the file of this patent UNITED STATES PATENTS 

